1. Field of the Invention
The present invention relates to a toner manufacturing method. In addition, the present invention relates to a toner and a developer including the toner for use in an electrophotographic image forming apparatus.
2. Discussion of the Background
U.S Pat. No. (hereinafter referred to as USP) U.S. Pat. No. 2,297,691, published examined Japanese patent applications Nos. (hereinafter referred to as JP-B) 42-23910 and 43-24748, etc. have disclosed various kinds of image forming methods using electrophotography. Typically, in electrophotography, an image is formed as follows:    (1) an electrostatic latent image is formed on an image bearing member (such as a photoreceptor including a photoconductive material);    (2) the electrostatic latent image is developed with a developer including a toner to form a toner image on the image bearing member;    (3) the toner image is transferred onto a recording material (such as a paper); and    (4) the toner is fixed on the recording material by application of heat, pressure or solvent vapors.
A full color image is typically formed by overlaying black, yellow, magenta and cyan toner images.
Carbon blacks are typically used as colorants for black toners. Recently, attempts to use particulate black metallic compounds as black colorants instead of carbon blacks have been made.
Japanese patent No. (herein after referred to as JP) 2736680 discloses a particulate black colorant having an average diameter of from 0.1 to 0.5 μm, and including a mixture of a Fe2TiO5 and a solid solution of Fe2O3—FeTiO.
JPs 3101782, 3108823 and 3174960 have disclosed black toners including a particulate magnetic iron oxide including FeO in an amount of from 25 to 30% by weight.
JPs 3224774 and 3261088 have disclosed particulate magnetites having a residual magnetization of not greater than 6 emu/g.
Published unexamined Japanese patent application No. (hereinafter referred to as JP-A) 2000-319021 discloses a particulate iron oxide including titanium therein.
JP-A 2002-129063 discloses a black colorant including a mixed phase crystal of rutile type titaniumdioxide (TiO2) covered by an iron titanium spinel (Fe2TiO4), and having a saturated magnetization of from 0.5 to 10 emu/g and a particle diameter of from 0.1 to 0.4 μm.
JP-A 2002-189313 discloses a black toner having a dielectric loss factor of not larger than 50, which includes a particulate metallic compound having a saturated magnetization of not greater than 30 emu/g.
JP-A 2002-196528 discloses a black toner including a particulate metallic compound having a saturated magnetization of not greater than 40 emu/g, in an amount of not greater than 20% by weight.
In terms of safety and fluidity of colorants, metallic compounds have an advantage over carbon blacks. In addition, a toner including metallic compounds has higher thermal conductivity than that including carbon blacks, i.e., the toner has good low-temperature fixability. Moreover, since metallic compounds have a higher specific gravity than carbon blacks, a toner including a metallic compound can be easily mixed with a carrier in a two-component developer. However, there has been a problem in that metallic compounds cannot be well dispersed in pulverization toners.